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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a440e6d516183395638fac954a482f1a3c1e2dce6c6948ef2ed8c541c83283' 
  AND token = 'wMdex7pgBsRRralvtWzMwSyrTR0AD7itjgBD+3SMdCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}