SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd18aafb9527e2dd8100acf540fe9076d41c155d252fc68837be7268089691e' 
  AND token = 'p1DkdFR2l8pawBRBLBhNwVfvMGr6Vy17Sd3XIjE44bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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