SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b664393bbc047996259c7d5a5a698b14be10301b79fd4336fc8fe9a2eab2f0c' 
  AND token = 'j+NI3V+GKyLjZwqpwEqEnA+EUbCsL2iZ7Y+O90NBvxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}