SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6debb930ac6bf62242eb15e5e4fead4e44f2814f39155bf93fd3ba40235370a3' 
  AND token = '1nkISWdJ5XRckTf7d4i/bt61jBnl/Cr+/NjGs1Kda4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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