SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf6700a32248200629b9cb07a0e31d2610aea628021cf88eb9695265769e2be' 
  AND token = 'gfK3LoanV9TU/v09L7SQEgla7nOF32dCkw+hq8Htyu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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