SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e528ee434214bf7b2ad1d1f0f6011632f417519890d88643f205465da647bd33' 
  AND token = 'GMbl1KWgnzZN6nes7bcxEhmmLJDcQv8lK+KPCysq+44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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