SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eaa79804be0af5280f9d333176fe059d4170df95cccce54311b457c7057208a' 
  AND token = 'Uy2ZFMGuAXlwe/WTC6xRN5cAxpmDNii1RZVYA5/zh9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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