SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed3645bafe8f8bc4728aea48114930dfea2b2981c661f190b4ca978433293ac2' 
  AND token = 'Tj4on8XeFkdJeEhxYLJlM0pkYR+GkSe/i/KE/6UIBYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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