SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd17b09aedde3797dfa921b3aa4290e455d4e88b59653fe825a83172b71982aaf' 
  AND token = 'LqXPpv6gQAveysAn0EBx8xS8jwHwTla+JD0UW/eEhno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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