SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6a0f877c68fd1658c987d0952188b352bf059811e713752d49aedf87b1624e8' 
  AND token = 'LTjbkkk+ggB1tWIRU2yFUr0GDFI5cU79ICFlPqCFJKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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