SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3b6354789f80562f4335075eb25bc7ab35247b77a0bdb3fdd0f05cf13068e06' 
  AND token = 'PRQ545XbUkk+LBq4NYdtilN9mbaYMde1Gky25b557BE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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