SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94eb01d63a5fdc80edd0e89f095c01debfd7af917a6e1feeea718ab63a847fc9' 
  AND token = '9T2Qmo/cDwvAFbvYDOWoI7GayQpms1Ti+DjeTU4D3qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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