SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bacf5b5a28ab5038c63d8e81f81fb9f9186215954ef371e4a0bd2a3867115360' 
  AND token = 'FqsRCRVhnAPl2I3Pdh2HI7lLDjQxr+sLLzz3hTjUNLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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