SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c55b41fa3d4184c94f6b9c3f7d096db3bc925dc08323dc363a1575b29c735685' 
  AND token = 'EkHKx2QPcfCVfENtH4zrMUzn2wmbdDTVN7ft5OOlwVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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