SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6478462ccabcb8aaa8c7fea5ec70e8ea5adec60990749429b53b1636c2351db' 
  AND token = 'EEyOttoA0Q8MRaeQzoKKxz/ciwh1JnGE/z1yrlRLKBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}