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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590bc2c5f31a217b6a982db3187edab20df3c05f9a1598a193f76c194e9cbfc4' 
  AND token = 'RQHNG3R6Dyc0zsz7XNZ8PFpZNRGOBeXi5XyqvZ1S6Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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