SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19945d1af81c988fa976b09c8df594e901d333f5f1828239d0e94760f03dcb84' 
  AND token = 'mWiu1XqXxtQYE1LrndVdtYq2v/b9QLWc/w+mNvAvJEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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