SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29da41bd47f16454afc17890ef19065ff40bb98fb0c17c343436252af8cf725c' 
  AND token = 'cpo/QG1PzzjKqfjxw9sibz5MMORzlhr5dzqgEQKzKUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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