SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eeb60f77eb67b39e8e71ac766844a0b3f6498b03a7ede75af66797de511f77e' 
  AND token = 'BDzObd285OPgMtYQx3GBLVzBewOqzSSMp1rxKpAPhZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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