SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75d0b9163d4a578c4fab0b223bb19b5e8073913ae428f64f51f4d32ad9ef474d' 
  AND token = 'BjeMaBZwYt++H398K17ZURYTuUljozmmJoHQIic/Udc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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