SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b886ed64a19339e8a832419758eb674d513220efe87584f19c90d186872c077' 
  AND token = 'zOoDjR2uVKWP5ue2xEZV79yCN3wiW75/SDvsnWJ+fJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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