SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fd3e95816033f3b263dc306039b2b5e560d64d207641d66024e28f3d3d795d2' 
  AND token = 'VMu1xtEotpKpatPUH60vy1l3MZAEUcytNFxSg2A0j+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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