SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f422971d893649a2db7cf80dda1217abaaf2c78638530583adfca3016de37bf0' 
  AND token = 'XIGHGvddt6DeEVljjkOZFt7BAQxlW0LoKSbKHm+o+zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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