SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fc6b8cd177d35f13f7c9dfd4ee2204722bc02b05ab5f8a045b6775506f52cf4' 
  AND token = 'Poh/4Y3SrnUPNlXZxVGJUQhEystqjucw629LPdDOiMY=' 
  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"
    }
  }
}