SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db4371ad579d7b33422a206c0c89cc4b1e18a830791a5457a36eb0604912c1d4' 
  AND token = 'A7O8Sl+RY8RbReQv3dtMQ6CfG/lYTeAM+J9fv2fSgcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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