SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ec3503672db3a7dc4e6c5d7b53429f1416e6543c619e16954537fa7aed28eb' 
  AND token = 'uzGlWwWcw2rZ0vZX2PA4RDwT/U3w5sxd4AgHSGalDbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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