SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2bd373c1575169dc7a6e49085954ab90af37dd9821920bf72c3a7c10aca20f28' 
  AND token = '0Go5hhE37aicroZ+5Q18aKsx1nydLsnMIKPyj13dKxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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