SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ae8b2f815b412d8bc60f2986258f971b09a10a5f995d0e9922948d57d4f97c2' 
  AND token = '18J2fAl0jV+BHgegtABulExUARAInuORhMeAvzDA7/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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