SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c9d3c571d368f07cfd87d5227f6a905e8d75f6b13dfc8ee4e474b72fb68d89a' 
  AND token = 'n8Uxx6NZBNr2rJ2B1LuBgvUCkiBwYpgkJtTuqwjwjvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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