SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7d946d3a0b87cbed293895b57ce41881b0a48d297bfa48a8f0b352d26945882c' 
  AND token = 'KR6hItxvrs/EqtzajGDU2dGHT/UucZZlHXlhsbga/9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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