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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd012f604ce2aad5f1f4e727eaa58f4f48d0ee0b844047990917dc651a7ccf56a' 
  AND token = 'mkfggpSHyqS0cWFZRzx3rk6GSy+PBxDwRTx9BRZtC0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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