SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83af59dcc184d7667f83d7e14ff207857650586bc98b934d37bf7e2e25a5e6d' 
  AND token = 'HQQULmWD6N1PBYP4j4TqaztgVuAqwuXnwCmppsIQ/Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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