SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bc6c2ed31e20b211b574d4bb86b432cafa7bd867d49359caf9f51e6f00313189' 
  AND token = 'MMHZ/lndHzA2tWzRSqKUweeDgl5//6avB421kFH1WcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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