SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '088da75c5aa79199e605c6322be5410b833b37b396fbb86a236b21985e35ef56' 
  AND token = 'HuPjOyiK/lWT4FP92+qELFFxLd66UxzvoPzvFi8Rh5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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