SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad6db537a6f07d8fe05ceba457d05842ad5f50d62446fa2060c90f170a11ed7f' 
  AND token = 'aCaOT6yC5rvn11pKILCqCCVp2njgFpNqHlH6YnqlwQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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