SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1ef94a1b5490a4bb8da4207c2f06c428dac49b5fe52db08596a0e13042d20c8' 
  AND token = 'UgNwBpgsoCSHBEOBQRnhHtmlfiwxvXqzNkt7d2EgDS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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