SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83fc1f96be9f6a40b72d0464f92f2f4667a2186098fd2b6f6674f8e49197a553' 
  AND token = 'oGMzfxnx4jjpSB9v3dp3W+hJ64Dwxz/2I4Kbh6Ymrko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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