SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '586250015228cb1e34c5fb4a1480556dfb1d1588cd3957c47378e2d78feaf2a0' 
  AND token = 'KzBwJUBN+vq8TxTRjrd+oRKFQdrLZnYnmT3Eb2i3SkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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