SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35eec3366aa7bcb442e4bf2be92bf6c664bdcf99524c100fcad7c834b919dc6c' 
  AND token = 'HaNp5RrWeGjNZ6eh7eUTzLtyqcRmhzSiCqua5sVXHwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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