SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '581b24a935cf6408bdca05b75eac772b3d65f907404a3c446a44ae7d3c0a3dcc' 
  AND token = 'wtfAC0T84RY6sOHRZR2qRKHnkV4NlODgEIQ7eBSxlzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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