SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f6dd269d5238ec7ddbc9e75c0fa73b3a3174c55feab6570bec1b57e434c6a935' 
  AND token = 'D5nPvVEDCLqDY/DbJYUnDAbfZXR8NmBmf5Tu6y7eNh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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