SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d71eb7db18a1bb4462e6a9e2c275d4769615f96aeaeff69907828444945a62' 
  AND token = 'JdxUqpm1hCV3V96B98otDPTESgXq8J0S6tVPZ61uL+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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