SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b96e802615934f297e746bae534cd03d70d0e79dbe83fbc096e77f9a88e486dc' 
  AND token = 'DYOasfoLbW9tJuh2Sgu9K42pLz+vlvJ6ccRjfdLinyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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