SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1871b782448b9db2e1cf3e90603d101babb2e5a9875b198c9201f2f794dc11' 
  AND token = 'xvmrnkUkDZa17PCBw5HPMomg6uaH1jqCTCgkq02YhOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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