SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb08dd5d4564916998aff557670a16f70479aeb6b700d14f9ed08eec6cc337fa' 
  AND token = '+wrlHucIXghmUUhKVXPrsIw/B2bC8NshwX7tfJmZdA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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