SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f00a6b5eed9220c4604966fcebbb0f4db4699cad1b18a1ac78d9c182309efca1' 
  AND token = 'euwuiFUf/UkP/jJn4P0qqEgA/06K1EgHqDCxnuBRM7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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