SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a8bb2158a630df2e391bdb7c66a4b4317b89d82993f4c3f758f2e154572c4f' 
  AND token = 'mzfTn14XL3A9gX9nfK3yEVlCCOWp1/JcMD+HAZpcOlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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