SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12931a59156e1b12a2e47086bc428e16d36ba0cee4f201042caa08bc0143f673' 
  AND token = 'IMU431p3UznY6USzZoCO/RN0sYl987BBz8qGlsI819I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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