SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac68bbb4c637ad46b2521f591ac79254fccf4df5c416baa1817ae158a75c5059' 
  AND token = 'fKXiPGjFzPOjXoBnuoHRYN1wDnIFPDcatahMLvdAK0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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