SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b4e8bd3f7f71a02086e8071d9069311d2f543061a3102231f3ad1db3f20e7c' 
  AND token = 'Z68iY/V2Jp5vs2W2vjb1BhUK9XE/wSZtNUqSRHAKCbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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