SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2713a56445975fb67e5fef0946d3aedf1dedefad1468d623177582247c2048f' 
  AND token = 'fXr5UiOFPhipEy+PFne1JdL+0tOnN3J/IGtV9EEZnYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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