SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a533ced1d4a1960d528a34c1ecbb189418344168cd87f800104ad16c12ed139' 
  AND token = 'AG3MMm2ZfuCsQDMcvQdeSIPTBlblYaLc6qzqVKZwChc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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