SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c2b7c124407ffc641f502bee30805a27844c2f5a1478ae681d539ad99d7f0231' 
  AND token = '71+6oNpHL660vnkzX52NlA9R4fiN+faO/HFTx0HoEqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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