SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dafdbe904bf98ca48849b8dbb723e4dd5b0d7e43a7ea394ee0055bda569fcf4e' 
  AND token = 'kLGRNBpiksjEimxTOAVYb0cUZXJkOzJx/iw1u8jaVVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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