SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93443b35972ec58b2073623822b2191c4c767f754cac142a0d8fafa9b7744268' 
  AND token = 'B+9QkG8/+crvy2uffj4GpotYufMzctzqOwaCU+KTO3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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