SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf167bc0557a49660454c857c16616333f84824133f375c3e9069b16c692ac66' 
  AND token = 'ebIf2AYgro/uqfioAJixP2jkMKlaTP+kQtge26sLRi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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