SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b2ed641c0d04824e91345f0a6e99764cd148bd712a9796df1486422d523d63e' 
  AND token = '5ngV4dtaDHuSEJXTwP76dmAPGUmYcTuavnXw0cLHe3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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