SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a03aef24bf9b0149fcacbe364b3cbc91cd0f6cf04588aac17601627a41660b' 
  AND token = 'kjx7MUSXB9kPTVWDg5YOjzyRweq7RkBqwUhQjqM4U5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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