SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142b0b2488f25ebcd8595e77cd62f9f01a84b1304d1acabc9bcd1ce71f4819ed' 
  AND token = 'c7z/aYKl+WEx7L1QFqgc+QUpvtqFZzbMjQXlzG223LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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