SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26e7e476a47b1d4374340d8bf66c560354c4260ea3bdca6d8ae77aa4374bd408' 
  AND token = '5BEF8zCGHVBdOqT+ZzKkykiddMr/rfCk8vkWKZNdvtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}