SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b6f57934390e23f6a312fe5ca772d4d94ef4b90ffdc89dfd9b3316ef39952ab' 
  AND token = 'qmLBiSZgT8IDfZFPqOCrlBMnzhBNtyg14msvNFX22Xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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