SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56543ea32eaa99984c5c01073ea50002de78cb087a2786434b258da7e475bde7' 
  AND token = 'FjyCUuLROTnyzy7KaxjSmooRJGMkVuT6wR9RGltcjs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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