SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52ab91828a23db26674cdfe8b03eeda4c5fb7fb56c33fbceb86225bcb8ee394f' 
  AND token = '+wdkzNwHa1QKmxPqbguMcKHT5Rdn5vl8YptvZ/7IjGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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