SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4cab309daba5f28c4b176f13789a17101749cf9d6e23edeaf6c954bbde32f33' 
  AND token = 'LZlquKYua6LfbY1Sl/owwV1BTISbrHiuijKoP9dGeUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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