SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '910c4267b13bc66c754b6b16d442f9896bfa0ea49c1e7b2514d613960dda26c5' 
  AND token = 'FwQTtaAEOKLxmes8gNr9d6RCEedxUrLPXelk5NEg2Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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